Pret: 50p off

With your own cup you could get one of its filter coffees for just 49p - that's a discount of more than 50pc.

The firm is also planning on offering its own reusable cup later this year, and may consider adding more china cups to some of its shops to cut the number of sit-in customers being offered paper ones by default.

Starbucks 25p off

Customers get 25p off all drinks if they eschew the paper cups. Currently less than 2pc of Starbucks customers take advantage of the initiative.

On the flipside, Starbucks will also begin charging an extra 5p to those who takeaway drinks its paper cups.

Paul: 25p off

Customers of the upmarket patisserie who bring their own cup get 25p off hot drinks reducing the cost of a "petite" espresso to £1.45 and a "grande" latte to £2.55.

The patisserie also sells its own reusable cups for £3.50.

Greggs: 20p off

The high street bakery gives cup-holding customers 20p off their hot drinks bought in every store.

This reduces the cost of a cup of tea to 80p or the most expensive large "speciality latte" to £2.25.

Customers who buy Greggs' own reusable cup for £2 will also get their first hot drink free.

Caffe Nero: double loyalty stamps

Fans of the Italian coffee chain won't get any money off but staff will give customers with reusable cups an additional stamp on their loyalty card. Once you've got nine stamps you get a free hot drink.

The chain also sells its own branded reusable cups online but they cost £10.

Universities and independent coffee shops

A number of other sites around the country are also trying to encourage the reuse of cups to reduce waste.

University College London's campus coffee shop offer students and staff a 10pc or 10p discount depending on which cafe they use.

Loughborough University gives students with reusable cups 10pc off. Leeds University offers a 10p discount.

It's also worth trying your local coffee shop for a discount as many offer similar price cuts.

Would you pay £34 for a reusable cup?

Starbucks' cup is £1 and Greggs charges £2.

Online prices start at a couple of quid for reusable cups. But some cost more than 15 times that.

For example a Mackenzie Childs porclain travel cup will set you back £34 from Selfridges.

Tea for free

Waitrose offers free tea and coffee to members of its loyalty programme when they shop. It asks those that sit in with their drink buy something from the cafe.

Those who sign up for Ikea's "family" membership scheme also get free tea and coffee Monday to Friday (it's 95p for everyone else).

Booths, the supermarket chain based in northern England, offers cardholders a free regular-sized hot drink everyday in selected stores from the takeaway coffee machine. Customers who want to drink it in one of its cafes must buy something in addition.